Known screw compressors are composed of a compressor element that is built onto a gearbox.
The compressor element is provided with a housing in which two helical rotors are mounted by their shafts on bearings that are lubricated by oil, to which end the compressor element is provided with an oil circuit with an input and an output for the oil.
The compressor element is also provided with a cooling jacket with an input and output to be able to circulate a coolant through the cooling jacket in order to be able to cool the compressor element.
The gearbox is provided with a housing with an incoming shaft for the coupling to a motor or other drive and the gearbox can be coupled in a torque-transmitting way to the shaft of at least one of the aforementioned rotors.
The compressor element and gearbox are built onto one another and to this end are provided with mounting surfaces that fit together with a seal therein for the external sealing of the housings with respect to the environment.
In the known screw compressors the mounting surfaces are often of a complex shape, which makes the sealing of them relatively difficult.
The inputs and outputs for oil and coolant for the compressor element are generally connected to an external supply and output for oil and coolant by means of external pipes in the form of tubes or hoses.
A disadvantage of such external pipes is that they represent an extra cost and that they can be an extra source of failures on account of the tearing or breakage of the pipes as a result of vibrations or similar, and on account of an increased risk of leaks at the location of the seals of the connecting flanges on both ends of the pipes.
An additional disadvantage is that for the connection of each connecting flange of a pipe, a connecting surface must be machined and that means must be provided to be able to tighten the connecting flange concerned against the connecting surface.
Another disadvantage is that the pipes can sometimes hinder the maintenance or certain repairs as for example they can obstruct easy access to bolts, sensors, filters and similar with standard tools.
Another disadvantage is that the pipes take up extra space and that to build the screw compressor into a cabinet or similar, the necessary space must be provided such that the set can be made less compact.
Another disadvantage is that pipes can sometimes be connected incorrectly, for example to an input instead of an output, which can lead to serious damage when bringing the screw compressor into service.